In this task, you are given an article. Your task is to summarize the article in a sentence.

Both heart rate and blood pressure increased in those who admitted extended time online - along with reported anxiety levels.
There was no such changes for those with no internet-usage problems.
Scientists said it suggested internet addiction is a real physical condition for some people.
The results of the study, which involved 144 participants aged 18 to 33, are published in the journal PLOS ONE.
Study participants had their heart rate and blood pressure measured before and after a brief internet session.
Their anxiety and self-reported internet-addiction were also assessed.
The results showed increases in physiological arousal on ending the internet session for those with problematically-high internet usage.
It follows a study by the two universities in 2013 which showed internet addicts can suffer a form of cold turkey when they stop using the web.
Prof Phil Reed, of Swansea University, said: "We have known for some time that people who are over-dependent on digital devices report feelings of anxiety when they are stopped from using them, but now we can see that these psychological effects are accompanied by actual physiological changes."
Prof Reed, who led the study, said there was an average 3-4% increase in heart rate and blood pressure, and in some cases double that figure, immediately on ending internet use, compared with before use, for those with digital-behaviour problems.
Although this increase is not enough to be life-threatening, the study said, such changes can be associated with feelings of anxiety, and with alterations to the hormonal system that can reduce immune responses.
The study also suggested these physiological changes and accompanying increases in anxiety indicate a state like withdrawal seen for many "sedative" drugs, such as alcohol, cannabis, and heroin.
Prof Roberto Truzoli, of Milan University, a co-author of the study, said: "Whether problematic internet use turns out to be an addiction - involving physiological and psychological withdrawal effects - or whether compulsions are involved that do not necessitate such withdrawal effects - is yet to be seen, but these results seem to show that, for some people, it is likely to be an addiction."
Some people spending excessive time on the internet can show physiological changes similar to drug withdrawal, researchers in Swansea and Milan found.

Xiao Gang was replaced by Liu Shiyu as the chairman of the China Securities Regulatory Commission (CSRC), state media report.
Mr Xiao was in charge when China's markets crashed in mid-2015.
At one point, the Shanghai and Shenzhen stock exchanges lost as much as 40% of their value.
Mr Xiao, 57, who became the CSRC chair in March 2013, has been criticised for mishandling the crisis.
Under his watch, China's new "circuit-breaker" mechanism, designed to limit any market sell-off, was deployed twice in January in response to the stock market fall, but then was scrapped altogether after it caused even more panic.
"Somebody needed to bear responsibility after the suspension of the circuit-breaker system," Zheng Chunming, a Shanghai-based analyst at Capital Securities Corp, told Bloomberg News.
Mr Liu, 54, was previously the vice-governor of China's central bank - the People's Bank of China - before becoming chairman of the Agricultural Bank of China, the country's third largest lender, in 2012.
On Chinese micro-blogging site Weibo on Saturday, commentators played on Mr Liu's name to speculate whether his tenure would bring about a "bull market" or leave behind a "dead fish".
The announcement of the new CSRC chair comes ahead of two high-profile events for China - next week's meeting of G20 financial leaders in Shanghai, and the annual gathering of China's legislature in March.
China has removed the head of its securities regulator as it tries to tackle major volatility in its stock markets.

Great Britain's Ryan will face Charlene Jones in the British Championships in Sheffield on Wednesday as she fights for the women's Lightweight title.
The 22-year-old told BBC Radio Derby: "You have to sacrifice a lot. You do think 'what if I lived a normal life?'
"I just say to myself 'suffer now and live the rest of your life a champion', that's what Muhammad Ali said."
Ryan, who is hoping to represent Great Britain at next year's Olympic Games in Rio, won a bronze medal at the European Games in Baku earlier this year.
The Derby boxer has already beaten her Welsh opponent twice, but Ryan is taking nothing for granted against Jones.
"She's very game. She will keep coming forward but I am looking to get the third win," Ryan added.
"I look back at videos with the coaches. Just because you've had a win against someone, you can't take it for granted.
"They could come with another game plan, so you have to be prepared."

Derby boxer Sandy Ryan says the sacrifices she has had to make will be worth it if it makes her a champion.

